• scheduling tasks, cron, ical and RFC-5545

    From christopher.dieringer@gmail.com@21:1/5 to nestor....@gmail.com on Mon Jun 5 23:28:05 2017
    On Friday, June 29, 2012 at 2:07:09 PM UTC-7, nestor....@gmail.com wrote:
    Hi Andrew,

    Just wondering if you can share your findings after almost two years? On Monday, September 13, 2010. I was hoping Quartz would respond to a similar demand ( https://jira.terracotta.org/jira/browse/QTZ-252 ) but from their latest source code all I can
    say is that the work hasn't even been started yet.

    Thanks!
    -Nestor

    5:36:32 AM UTC-4, Andrew wrote:
    I have a question about scheduling tasks. I am not sure what the
    correct newsgroup is for this question. I have posted it to a UNIX newsgroup because I am mentioning cron a lot.

    I have to implement a program that acts a bit like the UNIX cron
    daemon. It has a configuration that describes the scheduled tasks. It sleeps until it it time to kick off the first task, then it wakes up,
    kick the task off, re-schedules it for the next time if it is on a repeating schedule, then goes back to sleep again.

    So, why not just use cron then? Because I am looking into using the
    ICAL standard for specifying scheduled tasks, as per RFC-5545. This is
    much more powerful and flexible than cron, and has business-oriented facilities like scheduling for end of month, that cron cannot do.
    Plus, it is a OS-neutral standard. I am a UNIX man myself but I am currently working on Windoze and I do prefer it when general purpose
    apps are OS-neutral.

    I have come across libical, which implements a C API that can be used
    to process ical entries. I expect my solution will use libical, rather
    than me coding completely from scratch.

    So here is my question: does anyone know of a cron-like job scheduler
    that uses ical rather than the crontab format for specifying the job schedules?

    It seems to me that this problem is a general problem that ought to
    have a general solution. My googling has revealed very little. When
    people ask how to schedule tasks the most common reply is "use cron".
    Apple people tend to reply with "use ical" which is a GUI facility
    that comes with Apple Macs. And some people point out the well known problems with cron, particularly the one where it will not run the
    task unless the daemon itself is always running. I am aware of the
    anacron variant that solves this problem. Any ical-based solution
    should also deal with tasks that were not kicked off whilst the ical-
    based daemon was not running.

    Regards,

    Andrew Marlow

    Nestor, Andrew:

    Where did you guys land? I'm also searching for the solution!

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From florian.voit@gmail.com@21:1/5 to All on Thu Nov 8 05:10:54 2018
    Am Dienstag, 6. Juni 2017 08:28:06 UTC+2 schrieb christophe...@gmail.com:
    On Friday, June 29, 2012 at 2:07:09 PM UTC-7, nestor....@gmail.com wrote:
    Hi Andrew,

    Just wondering if you can share your findings after almost two years? On Monday, September 13, 2010. I was hoping Quartz would respond to a similar demand ( https://jira.terracotta.org/jira/browse/QTZ-252 ) but from their latest source code all I can
    say is that the work hasn't even been started yet.

    Thanks!
    -Nestor

    5:36:32 AM UTC-4, Andrew wrote:
    I have a question about scheduling tasks. I am not sure what the
    correct newsgroup is for this question. I have posted it to a UNIX newsgroup because I am mentioning cron a lot.

    I have to implement a program that acts a bit like the UNIX cron
    daemon. It has a configuration that describes the scheduled tasks. It sleeps until it it time to kick off the first task, then it wakes up, kick the task off, re-schedules it for the next time if it is on a repeating schedule, then goes back to sleep again.

    So, why not just use cron then? Because I am looking into using the
    ICAL standard for specifying scheduled tasks, as per RFC-5545. This is much more powerful and flexible than cron, and has business-oriented facilities like scheduling for end of month, that cron cannot do.
    Plus, it is a OS-neutral standard. I am a UNIX man myself but I am currently working on Windoze and I do prefer it when general purpose
    apps are OS-neutral.

    I have come across libical, which implements a C API that can be used
    to process ical entries. I expect my solution will use libical, rather than me coding completely from scratch.

    So here is my question: does anyone know of a cron-like job scheduler that uses ical rather than the crontab format for specifying the job schedules?

    It seems to me that this problem is a general problem that ought to
    have a general solution. My googling has revealed very little. When people ask how to schedule tasks the most common reply is "use cron". Apple people tend to reply with "use ical" which is a GUI facility
    that comes with Apple Macs. And some people point out the well known problems with cron, particularly the one where it will not run the
    task unless the daemon itself is always running. I am aware of the anacron variant that solves this problem. Any ical-based solution
    should also deal with tasks that were not kicked off whilst the ical- based daemon was not running.

    Regards,

    Andrew Marlow

    Nestor, Andrew:

    Where did you guys land? I'm also searching for the solution!

    I know this is a really old thread, but if somebody is still looking for a solution: I used python and the APScheduler library together with 'dateutil.rrule'. It created a custom rrule trigger for APScheduler which was just some lines of code.

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